1. Field of the Invention
The invention relates to a signal receiving system, a demodulation apparatus for a multi-carrier signal, and a detection method for the multi-carrier signal, and particularly relates to estimation of a band using offset values between pilot functions.
2. Description of Related Art
Through the developments of electronic technology, the bandwidth for transmitting audio and video information has increased significantly, and the request for high quality digital and audio signal transmission also increases as well.
In the conventional cable TV system, a transmission line is configured to transmit a variety of audio and video signals in a variety of formats. For example, in the conventional cable TV system, the same transmission line may need to transmit analog TV signals, Digital Video Broadcasting-Cable (DVB-C) signals with single-carrier modulation and Digital Video Broadcasting-Second Generation Cable (DVB-C2) signals with multi-carrier modulation.
For a spectrum regulation with 8 MHz (6 MHz) channel raster, the bandwidth of one DVB-C2 signal can be 8˜450 MHz (6˜338 MHz), which means that several DVB-C2 signals distributed at different frequencies and having different bandwidths could be simultaneously carried by the same transmission line. Thus, in the conventional technology of this technical field, a demodulating apparatus needs to be disposed at a signal receiving end to look for the bands of the transmitted signals. However, how to simply and accurately detect the bands of the carriers remains an issue for the designers in this field to work on.